Sulfur Dioxide, Hydrogen Sulfide Detection Tubes (SO2: 0.25-20 ppm, H2S: 1.25-120 ppm)

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Item #: 45S
MFG: GasTec
UOM: Box of 10 tubes (5 SO2, 5 H2S)
Min Order: 0
Order Qty: Must order in multiples of 1
$103.23 Was: $110.75
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Sulfur Dioxide, Hydrogen Sulfide Detection Tubes (SO2: 0.25-20 ppm, H2S: 1.25-120 ppm)

The Gastec 45S gas detection tube set contains 5 Sulfur Dioxide tubes with a measurement range of 0.25 - 20 ppm and five Hydrogen Sulfide tubes with a range of 1.25 - 120 ppm.

Name of Gas SO2 H2S SO2 H2S SO2 H2S
Measuring Range (ppm) 0.25 to 0.5 1.25 to 2.5 0.5 to 10 2.5 to 60 10 to 20 60 to 120
Number of Pump Strokes 2 (200 ml) 1 (100 ml) 1/2 (50 ml)
Correction Factor 1/2 1 2
Sampling Time 4 min 2 min 1 min

  • Detecting Limit: SO2/H2S tubes : 0.05 ppm(2 pump strokes)
  • Color change:
    • SO2 tube: Yellowish green to Yellow
    • H2S tube: White to Brown
  • Corrections for temperature & humidity: Unnecessary
  • Relative Standard Deviation:
    • SO2 tube: 10 % (for 0.5 to 2 ppm), 5 % (for 2 to 10 ppm)
    • H2S tube: 10 % (for 2.5 to 20 ppm), 5 % (for 20 to 60 ppm)
  • Shelf life: 3 years
  • Reaction Principle:
    • SO2Tube:
      • SO2 + BaCl2 + H2O → BaSO3 + 2HCl
      • HCl + Base → Chloride
    • H2S tube:
      • H2S + Pb(CH3COO)2 → PbS + 2CH3COOH
  • Note: When used, connect the SO2 tube and the H2S tube (with both ends broken off). This twin tube can measure SO2 and H2S simultaneously.

Possible coexisting substances and their interferences:


SO2 tube

Substance Concentration Interference Changes color by itself to
Nitrogen dioxide ≧ 5 ppm No Pale purple
Carbon monoxide, Nitric oxide No No

H2S tube

Substance Concentration Interference Changes color by itself to
Mercaptans No No